'94 CBR 900RR Project

Discussion in 'WERA Vintage' started by chobes, Apr 15, 2022.

  1. chobes

    chobes Well-Known Member

    Recently picked up a '94 RR as a donor to a project I've long wanted to do - swap a 900RR engine into an F2 or F3 frame. After looking into it further, I've decided to rebuild the RR. No hurry on this project, as I still have an F3 project to finish up, and an F3 that's completed so I can ride. First things first, some pictures. And then to decide what to do with the engine. Turns out that it's seized, thus the great deal on the bike. Do I rebuild the engine, or swap it with some eBay replacement? I'm open to all suggestions, first RR that I've owned.

    IMG_1118.JPG IMG_1066.JPG IMG_1124.JPG
    ToofPic likes this.
  2. fastedyamaha

    fastedyamaha Well-Known Member

    I guess that it would depend on how cheaply you can buy a flea bay motor vs the time, energy, and money involved in fixing it yourself.
    chobes likes this.
  3. chobes

    chobes Well-Known Member

    That's exactly what I'm looking into at the moment. Used motors run from $850-1,500, need to see what a rebuild is going to cost me. Easiest option is an eBay motor, but never really know what you're going to get.
  4. fastfreddie

    fastfreddie Midnight Oil Garage

    Good, fast and/or cheap. Pick two. :D

    You got the bike cheap. I say spend what it takes to make it good and fast.
    chobes likes this.
  5. TurboBlew

    TurboBlew Registers Abusers

    looks like it had a rough life.
    I would tear down what you have just to see whats up. You can recon the crank & rods... get new pistons if the bores arent too bad, address the trans issues... and so on.
    Cant imagine finding a low mile 25 year old engine these days
  6. fastfreddie

    fastfreddie Midnight Oil Garage

    I was gonna say stolen ghetto stunta but I didn't want to perpetrate stereotypes.
    I bet there are a lot of oil-starved bearings and the dogs on the gears have round ears.
    Oh, almost forgot the hammered valvetrain from extensive bangin' off the "red" limiter.
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  7. pawpawrc

    pawpawrc Well-Known Member

    Yeah rod bearings (#3 esp) like to go on these with just a little bit of wheelies. Engine is super easy to redo, depends on parts availability nowadays. If your cylinders need help/replate, I’ll be able to help with that soon.
    chobes likes this.
  8. chobes

    chobes Well-Known Member

    I'm not in a hurry with this, so I'll most likely tear the engine apart just to take a look. Was great to find the reason why the starter wouldn't spin, not sure if that can be fixed or if I'll need to source a new block to get around that issue.

  9. TurboBlew

    TurboBlew Registers Abusers

    can you spin the motor by ratchet on the stator?
  10. fastfreddie

    fastfreddie Midnight Oil Garage

    You now what they say, ugly goes all the way to the bone.
    Good luck with the project. Sincerely.
    chobes likes this.
  11. chobes

    chobes Well-Known Member

    Nope, it’s seized up good and proper. I pulled the plugs and have emptied a can of PB Blaster into it, and some WD40.
  12. britx303

    britx303 C.Thomas is Monica!!

    I have a ‘93-ish cbr1000f rat bike I’m doing nothing with, and looking to clear it with a bunch of others. ZERO clue if those engines fit, and I’ve never ran this bike so I don’t know what condition the engine is in other than not seized. All yours if you want it, but right up front again, no clue on engine condition, but bike is dog ugly.
    chobes likes this.
  13. chobes

    chobes Well-Known Member

    Thanks for the offer, don't think I can use any of those parts.
  14. YoshiHNS

    YoshiHNS Mr. Slowly

    The answer is to always go for the full send. Tear down this motor and see what's up. Either fixing this squiddie wrecked engine, or some other one. And sounds like this one is a candidate for a +2mm.
  15. TurboBlew

    TurboBlew Registers Abusers

  16. chobes

    chobes Well-Known Member

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  17. chobes

    chobes Well-Known Member

    I've sprayed the engine a few times, even poured some Honda ATF into it - today I put a breaker bar on the stator and it broke loose, will be interesting to see what I find when I pull it apart. That being said, I've found a deal on a running bike, will arrive in a week or two, looking forward to making some progress on this bike.
    britx303 likes this.
  18. dave3593

    dave3593 What I know about opera I learned from Bugs Bunny

    If the top end is sized from damage then a top end rebuild at a minimum. If it is stuck from setting (rust) it may need a little or alot. I brought a bike that the engine was stuck tight. All it needed was a careful disassembly, sandpaper clean up and a couple gaskets to run well again but it was not used for racing. It could be this easy all the way to clapped out engine and trans.
  19. chobes

    chobes Well-Known Member

    Pulled the carbs, what a lovely sight

    IMG_1328.JPG IMG_1329.JPG IMG_1330.JPG

    On a positive note, it has stock jets so I can use those to dial in the donor bike engine before I swap it over.

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